I spoke to Meg-John Barker about her new book, which questions pretty much everything you think you know about sexuality.

We have strange ideas about gender and sexuality. Most of us expend great energy wondering if we're normal, if we're too "masculine" or too "feminine", if we're slags or if we're weirdly frigid. How we got these ideas and the ways in which they can be dismantled is the subject of Meg-John Barker's new book, Queer: A Graphic History . The graphic non-fiction is a speedy aerial view of queer theory, from its founders to the current debates.

Barker, an author, psychotherapist and activist-academic, is a key figure in UK queer politics and has teamed up with artist Julia Scheele to create an utterly un-dusty tome that questions everything from the way we categorise our sexual desire to the foundations of happiness.

I caught up with them for a chat.

VICE: I loved being made to think about the idea that identities aren't fixed, that they're contextual and may change over time. It's hard not to see your sexuality as intrinsic to who you are, and not changeable. "I just fancy who I fancy." What do you think a world would look like where people were more open to flux and change? Meg-John Barker: I so want to live in that world! 43 percent of young people see themselves as somewhere in between being attracted solely to men or to women. So it's nearly the majority. It baffles me that we still insist on this gay/straight binary when so many people don't experience themselves in that way and experience their gender identity and sense of who they're attracted to shifting over time.

It seems like such a journey doesn't it – when we're still battling for basic sex education in schools, to a place where we're talking about gender and sexuality like this? That's what feels frustrating, especially when we look at the stats on mental health. Those who are outside the binary of gender or sexuality have a massive toll taken on their mental health. Forty percent of non-binary people have attempted suicide. Every time they do a study, bi people come out much worse in terms of mental health because they just don't see themselves represented anywhere, and when they do it's in terms of horrible stereotypes.

The argument made by TERFS (Trans Exclusionary Radical Feminists – feminists who deny that trans people's self-affirmed genders are valid, i.e. Germaine Greer and Julie Bindel) here would be that there's nothing mutable about having a particular body; that biological sex is a solid thing with visible markers and that ignoring it is futile. Is there any way of reconciling the arguments? I think so. It seems like the TERFs – for want of a better word – are mostly arguing for people to be whoever they are; that women and girls should have equal rights, but also that there should be diversity within that category. And in a way that's not far away from the queer argument that everyone should be able to be whoever they are in whatever gender they are. What's the sticking point?

I think a lot of TERFs have this sense that trans activists want to push everyone into surgeries and medical transitions, and that just isn't the case – not that there's anything wrong with those who need those things getting them. And also this idea that if somebody is a trans woman they'll have this basic maleness inside them that makes them violent. Those are the "bathroom bill" kind of concerns, but there's no evidence to support this. And again, it's a very essentialist understanding of gender, because there's a massive diversity in every gender around how violent people are.

I always feel like it boils down to vulnerability. We have our experiences in life that make us cling to certain ideas because we believe they'll make the world a better place. But it's very hard when one person's version of that excludes another's. Trans people are clearly some of the most vulnerable people in society – to suicide and homicide. They are really not the right people to pick on if you want to make the world a better place.

Would there be a more meaningful way of categorising the way we like to have sex than simply whether you fancy men, women or another gender? Your book made me want to read Eve Kosofsky Sedgwick, who asks this question. Looking at how sexual you are or how much you experience sexual attraction is a really useful one, because it makes it OK to not experience sexual attraction or to not want sex. Given that we're in a world of so much sexual compulsivity – and people do a lot of non-consensual things because they think they should be having sex – it would be really helpful to encourage people to realise it's fine to not have sex, or to be anywhere on that scale. For other people it's more about roles and power dynamics and sensations.

Thinking about your sexuality in this multifaceted way takes us into a much more interesting engagement with our own sexuality instead of being scared of it and just trying to be "normal".

You talk about the difference between assimilationist activism – that simply argues that, being gay, for instance, is perfectly "normal" and "respectable" – and the sort of activism that points out the underlying flaws in the way society sees sexuality and gender. Where do you think the best activism has been that manages to do this effectively? Shiri Eisner's book Bi: Notes for a Bisexual Revolution is really good on this stuff. The assimilationist way of doing bisexual activism would be saying "we're not greedy", "we're not just going through a phase", "we are sure of our identities". Kind of myth-busting.

And Eisner says that the problem with myth-busting is that it keeps those assumptions in place. To say "bi people aren't promiscuous" is to suggest there's something wrong with being promiscuous. So she takes it a step further and says, yeah there's no evidence that bi people are more promiscuous, but hang on, what's wrong with being promiscuous? While there's no evidence that bisexuality is just a phase, actually maybe everyone's sexuality is just a phase.

Sara Ahmed's work on happiness is incredible; the idea that we can and should challenge society's happiness tick-boxes. So I guess anybody whose life disrupts normative assumptions should get queer theory? Yes, to some extent anybody who's questioning sex or gender, or even the escalator model of relationships – dating, getting married, having children – is, in a way, queer. My work as a therapist suggests that at some point in nearly everyone's life something makes them realise that there's a problem with that model.

And it goes way beyond gender and sexuality. The same challenges exist around class, race and disability. How can we make a world that's accessible to the full range of bodies? How can we make a world where the class that somebody's born in doesn't massively restrict their lives? How can we make a world in which all the cultural groups can co-exist? There are no easy answers, but it's the same set of questions. How can we include everybody?